1. Field of the Invention
The present invention relates to a prosthetic material for tooth or bone loss. More particularly, it relates to a prosthetic material which causes less tissue reaction, has high affinity and firmly locks to vital tissue and has an excellent durable hard structure and a preparation thereof.
2. Description of the Prior Art
Prosthesis of a tooth missing or an injured part of bone with an artificial material has been known since ancient times. In spite of various efforts for a long time, there still remained various problems.
As a substituent for hard tissue of a living body, metallic materials such as SUS316 stainless steel, cobalt-chromium alloy, titanium, titanium alloy, tantalum, zirconium, gold, silver, and platinum; organic hard materials such as high density polyethylene, polytetrafluoroethylene, and polymethyl methacrylate; other composites such as composite resin; and inorganic materials such as ceramics, bioglass and carbon have been studies and developed. Certain materials have been practically used.
Various characteristics are required for prosthetic materials depending upon a part for application, a configuration and a size. The applicability is different for each material.
One of the problems in the application of an artificial prosthetic material in a living body, is the loosening of the prosthesis which occurs after a certain period of time.
For example, in a repair of a fracture of bone or an artificial articulation for fixing a hard artificial prosthetic material to a bone, it has been known to employ (1) a self-locking method of fixing a prosthetic material to a bone tissue in a structural or configural form; (2) a method of mechanical fixing with a screw or spike; and (3) a method of bonding a prosthetic material to a bone with a bone cement. Thus, in these methods, certain loosening has happened for a long time and the prosthetic material must be substituted, even though the prosthetic material itself has not deteriorated.
In the other case, a dental therapy for embedding an implant in alveolar bone and fixing a crown on it to restore masticating function has been known. Various hard materials have been used as the implant material and various configurations such as screw forms, cylindrical column forms, pin forms, natural tooth root forms and blade forms have been considered depending upon the property of the material. In order to receive the masticating pressure which is highest in a living body, it is necessary to increase a contact area between the implant and the bone.
One of the inventors has studied various implants having various configurations and structures by using various materials. Certain materials do not have enough strength and other materials do not have enough affinity for a biotissue. A satisfactory material has not yet been found. Thus, the inventors have further studied and have succeeded in the preparation of an artificial prosthetic material which has superior characteristics to the conventional materials used in the prior art. The characteristics of the prosthetic materials of the present invention result from the combination of the deposition of pyrolytic carbon which imparts remarkably high strength to the prothesis and the design of a porous structure for the firm-locking of the prosthesis to the vital tissue due to the high affinity of carbon materials to vital tissue.